Gravity was definitely one of the most talked about movies of 2013, snagging nominations at almost every award show. But what if Gravity would have been a little bit different? We mean, what if George Clooney and Sandra Bullock weren’t the leading stars? Well, that almost happened!

The film’s director Alfonso Cuaron revealed that the original casting choices wereRobert Downey, Jr. and Angelina Jolie! So what happened? Angelina dropped out of the project due to scheduling conflicts while she was making her directorial debut for In the Land of Blood and Honey. That’s pretty understandable considering she was directing her first film, but Robert? There were some other issues that he came across.

RDJ backed out on Gravity because, due to the film’s technology, it didn’t allow him to improvise the script. “It became very clear that, as we started to nail the technology, or narrow the technology, that was going to be a big obstacle for [Robert’s] performance,” Alfonso said. “I think Robert is fantastic if you give him the freedom to completely breathe and improvise and change stuff. [But] we tried one of these technologies and it was not compatible. And, after that, we [had a] week that we pretended as if nothing was happening and then we talked and said, ‘This is not going to work. This is tough.’”